Earlier quoted context omitted.
Wealth of nations, book 1, actually. "toil and trouble" could be interpreted as "labour". I certainly take that interpretation. though Smith really didn't make much use of the labour theory of value, as he thought it would be less relevant in an advanced economy. Riccardo and especially Marx developed and used it much more. (For Marx see the first part of Capital)
The idea of "value" independent of price is something treated by Marx as a normative claim that neither Adam Smith or Ricardo developed. When Ricardo or Adam smith talked of "value", they just meant "price" but in some notional unit of currency which was irrelevant to the discussion at hand. E.g. they wanted to discuss prices in a barter economy. Adam Smith explored the labor theory of value in the context of primiti…
Price of land is determined when looking at the world as a whole (margin of production), so it can't be measured in a simple microeconomic laboratory experiment.
It can actually be studied using models, but one would have to go back to Smith and Ricardo and add the third factor of production (land) back into the equation. Which was removed by marginalists for simplification to study simple markets of bananas and yogurts.
The modern economic foundations simply don't have the tools to study land markets, so they will always fall into the trap of a drunk man looking for keys under the lamppost only.